The long-term objective of the proposed research is an understanding of one of the simplest of mechanoenzymes, namely, the bacterial flagellar motor, the organelle that enables bacteria to swim and to display the simple behavior of chemotaxis. An understanding of this system contributes to an understanding of several basic biological principles, such as energy conversion, device switching between states, organelle assembly, the structure of macromolecular complexes, and the genetic control of complex integrated systems; together with studies in other laboratories, it also contributes to an understanding of sensory processing and of modulation of effector organelles by such information. Furthermore, it assists and complements studies being undertaken elsewhere, concerning the ecological consequences of motility and chemotaxis of bacteria, including human pathogens and symbionts, plant pathogens and symbionts, and free-living species. Since many of these species are not as well understood genetically as Salmonella typhimurium and Escherichia coli, the detailed molecular information that can be generated in the latter two species is extremely useful in guiding the more applied environmental research. The immediate goal is the identification of all genes involved in flagellation and motility, identification of their products, determination of their location in the cell, and determination of their functional role. Because of the complexity of this "simple" system (ca. 40 genes) this is a considerable task, and although much has been accomplished in this regard already, much remains to be done. The approaches will include genetics, molecular genetics, biochemistry, and electron microscopy. Cloning of the relevant genes will be completed, and their products identified by a minicell method. Cloning of the relevant genes will be completed, and their products identified by a minicell method. Characterization of the flagellar basal body will be continued in terms of identity and numbers of subunits of each component. Components that are known genetically, but are not in the flagellum as currently isolated, will be sought using less extreme isolation protocols. Physical interactions between different components will be studied by a gel overlay technique analogous to western blotting. An attempt will be made to determine the means by which the flagellar motor is anchored to the cell surface.